Screw it all the way in, then back it out a turn and a half. Adjust it to achieve lowest idle without stalling. If you are more than 2.5 turns out, or less then .5 turns from all the way in you may need to adjust your pilot jet accordingly.

Disclosure, I've never worked on your specific carb, and my experience comes from fighting with a kehein on my YZ250 for a couple years. So, my above settings may not directly translate.